The present invention relates to a motorcycle, and in particular, to the arrangement of an air cleaner on a motorcycle.
In the case of a motorcycle which carries what is called a "V-array engine" in which the cylinders are mounted in a V-array, it is difficult to arrange the intake system. In accordance with the prior art, it was usually the case that the air cleaner was provided in such a way as to transversely project from the body of the motorcycle, but it is not preferable to do so because the appearance thereof is not good. The impression is given that the bike is wide, the slimness of the body of the motorcycle is spoiled and the feet of the rider strike against the air cleaner. In addition, since an intake system is required for each of the cylinders, there is also a drawback in that the cost becomes high.
In accordance with the prior art, there is known a construction such that three or four fastening stays extend from the frame body and the air cleaner is mounted thereon. However, since the number of parts increases with such a mounting arrangement, and the constitution thereof is complex, the assembly operation is not efficient and the cost becomes high.
Since there are also various conditions on the intake air in the system, it is in particularly difficult to arrange the suction port of the air cleaner.
For example, the conditions on the intake air of the air cleaner are as follows:
1. If the temperature of the intake air is high, the air density is low. Thus, since it becomes impossible to obtain high power output, it is required that the temperature of the intake air be lowered.
2. A turbulent flow is caused, for example, when the moving motorcycle travels against the wind, thereby making it impossible to draw in the air at a constant pressure. As a result, it becomes impossible for the carburetor to be set. Therefore, it is required that there be no variance in the pressure of the air in the suction port.
3. It goes without saying that it is required that no water be admitted with the intake air.
In the case of an air cleaner provided with an elliptic filter element, the intake air passes by only one portion of the element because the suction duct is close to the element. As a consequence, it is impossible to use the whole element and there is caused an inconvenience, for example, in that the life of the element becomes short as the air resistance increases.
Not only the case, but also the cover are made of non-transparent materials in the conventional air cleaner. On the other hand, when the filter element has become dirty, it is required to replace it with another one. In the past, the cover was removed to inspect the interior portion of the air cleaner to confirm whether the element was dirty or not, and this operation is troublesome.